A heat exchanger is used for efficient transfer of heat from one medium to another and it can consist of thousands of small pipes through which gas or fluid is transferred. These narrow pipes need to be inspected and cleaned thoroughly from time to time. This is performed manually with the current technology and the heat exchangers need to be disassembled in order to get access to the narrow pipes.

At SINTEF Applied Cybernetics we have looked at how such an inspection and maintenance task may be automated. One solution is to gain access to the inside of a heat exchanger through small inspection holes in the tank. With this in mind, we developed a demonstrator for a robotic system that may access a heat exchanger through such a small inspection hole, but nevertheless be able to access a large workspace inside the tank. Hence, the robot may inspect each of the narrow pipes inside a heat exchanger. In addition, it should be possible to conduct eddy-current analysis with the help of the robot and pipes that need more attention can be located and dealt with.

The demonstrator is capable of inspecting a long horizontal row of small holes. The robot can cover a 2 m long row even though it only needs a hole of 4 cm in diameter to enter a heat exchanger. Moreover, the robot is able to inspect both pipes that are directly in front of it in addition to holes far out on the sides – even though the robot is placed very close to the row of holes. A small video camera is mounted on the tip of the robot in order to be able to inspect the small holes.